1. Field
The present invention relates to wireless communications. More particularly, the present invention relates to a novel method and apparatus for providing multiple levels of quality of service at a mobile station in a wireless packet data network.
2. Background
The use of code division multiple access (CDMA) modulation techniques is one of several techniques for facilitating communications in which a large number of system users are present. Other multiple access communication system techniques, such as time division multiple access (TDMA), frequency division multiple access (FDMA) and AM modulation schemes such as amplitude companded single sideband (ACSSB) are known in the art. These techniques have been standardized to facilitate interoperation between equipment manufactured by different companies. Code division multiple access communication systems have been standardized in the United States in Telecommunications Industry Association TIA/EIA/IS-95-B, entitled “MOBILE STATION-BASE STATION COMPATIBILITY STANDARD FOR DUAL-MODE WIDEBAND SPREAD SPECTRUM CELLULAR SYSTEMS”, and referred to herein as IS-95. In addition, a new standard for CDMA communication systems has been proposed in the United States in Telecommunications Industry Association (TIA), entitled “Upper Layer (Layer 3) Signaling Standard for cdma2000 Spread Spectrum Systems, Release A—Addendum 1”, dated Oct. 27, 2000, and referred to herein as “cdma2000.”
The International Telecommunications Union recently requested the submission of proposed methods for providing high rate data and high-quality speech services over wireless communication channels. A first of these proposals was issued by the Telecommunications Industry Association, entitled “The IS-2000 ITU-R RTT Candidate Submission.” A second of these proposals was issued by the European Telecommunications Standards Institute (ETSI), entitled “The ETSI UMTS Terrestrial Radio Access (UTRA) ITU-R RTT Candidate Submission”, also known as “wideband CDMA” and hereinafter referred to as “W-CDMA.” A third proposal was submitted by U.S. TG 8/1 entitled “The UWC-136 Candidate Submission”, hereinafter referred to as “EDGE.” The contents of these submissions is public record and is well known in the art.
IS-95 was originally optimized for transmission of variable-rate voice frames. Subsequent standards have built on the original IS-95 standard to support a variety of additional non-voice services including packet data services. One such set of packet data services was standardized in the United States in Telecommunications Industry Association TIA/EIA/IS-707-A, entitled “Data Service Options for Spread Spectrum Systems”, incorporated by reference herein, and hereafter referred to as “IS-707.”
IS-707 describes techniques used to provide support for sending Internet Protocol (IP) packets through an IS-95 wireless network. Packets are encapsulated into a featureless byte stream using a protocol called Point-to-Point Protocol (PPP). Using PPP, IP packets can be transported over a wireless network in segments of arbitrary size. The wireless network maintains PPP state information for the duration of the PPP session, or as long additional bytes may be sent in the continuous byte stream between the PPP end points.
Such a continuous byte stream is subsequently encapsulated into a series of IS-95 frames using a protocol called Radio Link Protocol (RLP). RLP includes an error control protocol that uses negative acknowledgments (NAKs) by which the receiver prompts the sender to retransmit lost RLP frames. Because the RLP error control protocol uses retransmissions, RLP data transmission generally exhibits a variable transmission delay from sender to receiver. A modified form of RLP called Synchronous RLP (SRLP), in which no NAKs and no retransmissions are sent by sender or receiver, is well known in the art. The frame error rate in SRLP is greater than that of RLP, but the transmission delay is kept to a minimal constant.
A remote network node such as a personal or laptop computer (PC) connected to a packet-data-capable wireless Mobile Terminal (MT) may access the Internet through a wireless network in accordance with the IS-707 standard. A combined PC and MT is defined herein as a Mobile Station (MS). Alternatively, the remote network node such as a web browser may be built-in to the MT, making the PC optional. A wireless device may comprise any of a number of types of devices including, but not limited to an MT, MS, PC card, personal data assistant (PDA), external or internal modem, or wireless phone or terminal. The wireless device sends data through the wireless network, where the data is processed by a Packet Data Serving Node (PDSN). The PPP state for a connection between a wireless device and the wireless network is typically maintained within the PDSN. The PDSN is connected to an IP network such as the Internet, and transports data between the wireless network and other entities and agents connected to the IP network. In this way, the wireless device can send and receive data to another entity on the IP network through the wireless data connection. The target entity on the IP network is also called a correspondent node. The interaction between a wireless device and the PDSN have been standardized in EIA/TIA/IS-835, entitled “Wireless IP Network Standard,” dated June, 2000, and referred to herein as “IS-835.” One skilled in the art will recognize that, in some networks, the PDSN is replaced with an Interworking Function (IWF).
IP service is provided to the PPP link layer by an IP service layer. The IS-835 standard defines two methods of IP service for accessing Public and Private networks: Simple IP and Mobile IP. Simple IP is a service in which the user is assigned a dynamic IP address from the local PDSN and is provided routing service by a service provider network. The user retains its IP address as long as it is served by a radio network that has connectivity to the address assigning PDSN. There is no IP address mobility beyond this PDSN. Mobile IP is a service in which the user is provided routing service to a Public IP network and/or secure IP routing service to pre-defined private IP networks. The wireless device is able to use either a non-zero static IP address or a dynamically assigned IP address belonging to its home IP network Home Agent. The wireless device has a non-zero static Home Agent Address assigned regardless of whether the mobile station has a static or dynamic Home Address. The wireless device is able to maintain a persistent IP address even when handing off between radio networks connected to separate PDSNs.
In order to provide more complex wireless network services, there is an increasing desire and need to provide different types of services simultaneously through a single wireless device. Examples include simultaneous voice and packet data services. Examples also include multiple types of packet data services, such as simultaneous web browsing and video conferencing. At the same time, technological advances are increasing the bandwidth available through a single wireless channel between a wireless device and the wireless network.
However, modern networks are not yet capable of supporting simultaneous packet data services having substantially different grades of service through a single wireless channel. For example, delay sensitive applications like video conferencing and voice over IP are optimally sent without RLP retransmissions in order to reduce the magnitude and variability of packet delay through the network. On the other hand, applications such as FTP, e-mail, and web browsing are less delay-sensitive, so are optimally sent using RLP retransmissions. Current wireless standards adequately support a wireless application that requires any one of several grades of service, known as a Quality of Service (QOS), in a single wireless device. Current standards cannot, however, support multiple QOSs in a single wireless device. Multiple QOSs in a single wireless device are required for the use of multiple applications where each application requires a different QOS, and by single applications that use multiple QOSs for differing levels of RLP transmission delay sensitivity. Multiple QOSs are not currently supported in a single wireless device because each QOS would require its own specifically configured PPP connection including an IP address and IP stack. Multiple IP stacks operating in a single wireless device cause IP address confusion that produces difficulty in the routing of IP packets to their proper PPP termination points by the PDSN. Thus, there is a need in the art for a way of supporting multiple PPP connections in a single wireless device, where the PDSN is able to differentiate individual PPP session termination points operating under one IP stack within a wireless device.